Most healthy 25 year olds don't stay up at night worrying whether they are going to develop diabetes in middle age. The disease is not on their radar, and middle age is a lifetime away.
As it turns out, many should be concerned. Researchers at Northwestern University Feinberg School of Medicine have found that young adults (18 to 30 years old) with low aerobic fitness levels --as measured by a treadmill test -- are two to three times more likely to develop diabetes in 20 years than those who are fit.
The study also shows that young women and young African Americans are less aerobically fit than men and white adults in the same age group, placing a larger number of these population subgroups at risk for diabetes.
"These young adults are setting the stage for chronic disease in middle age by not being physically active and fit," said Mercedes Carnethon, lead author and assistant professor of preventive medicine at Northwestern's Feinberg School. "People who have low fitness in their late teens and 20's tend to stay the same later in life or even get worse. Not many climb out of that category."
The study will be published in the July issue of Diabetes Care.
In the study, the most important predictor of who will develop diabetes is the participants' Body Mass Index (BMI), a measure of the body's fat content.
"The overwhelming importance of a high BMI to the development of diabetes was somewhat unexpected and leads us to think that activity levels need to be adequate not only to raise aerobic fitness, but also to maintain a healthy body weight," Carnethon said. "If two people have a similar level of fitness, the person with the higher BMI is more likely to develop diabetes."
Carnethon stressed that unfit young adults can avoid a future with diabetes by exercising and losing weight. "Improving your fitness through physical activity is one way you can modify your body fat," she said. "Research shows that combining regular physical activity with a carefully balanced diet can help most people maintain a healthy body weight and lower the likelihood of developing diabetes."